<script setup>
import { ref } from 'vue'
let num = ref(2)
const btn = () => {
  num.value += 2
}
</script>
<template>
  <div>
    御剑乘风来,除魔天地间!===vue3==={{ num }}
    <button @click="btn">按钮</button>
  </div>
</template>
